With a budget of $10m (£5.7m), Valley of the Wolves Iraq is the most expensive film ever made in Turkey - and it is pulling record crowds.

At one of Istanbul's biggest multiplex cinemas the blockbuster is showing on five separate screens and nearly all the seats are sold out. It's the same story across the country.

"I'm back to see it for the second time already," says one student, waiting impatiently outside Screen 10.

"It is anti-American, but we already know what they've done in Iraq. That's the reality. Now we can see it on screen."

The movie opens with a real-life incident: the arrest in July 2003 of Turkish special forces in Sulaymaniyah, northern Iraq.

The soldiers were led out of their headquarters at gunpoint, with hoods over their heads. America later apologised, but it appears the offence ran deep.

The film has turned out to be a sensation at the box office

At the time Turkey took the incident as national humiliation. In this film the fictional hero sets out for revenge.

From then on, the action pits good Turks against very bad Americans, in a mix of fact and fiction with a deeply nationalistic flavour.

US violence

In one scene, trigger-happy US troops massacre civilians at a wedding party.

In another they firebomb a mosque during evening prayer. There are multiple summary executions.

And for the first time, the real-life abuses by American soldiers at Abu Ghraib prison are played out on the big screen.

This film poisons the climate in a way that enhances jingoistic nationalism among Turks

Middle East expert Cengiz Candar

Even the doctor - played by Gary Busey - is evil, removing human organs from Iraqi prisoners to send to patients in the US, Israel and Britain.

"Our film's a sort of political action," explains script-writer Bahadir Ozdener at the production company's stylish office on the Asian side of Istanbul.

"Maybe 60 or 70% of what happens on screen is factually true. Turkey and America are allies, but Turkey wants to say something to its friend. We want to say the bitter truth. We want to say that this is wrong."

In a mainly Muslim country that has enjoyed a long strategic partnership with the US, Valley of the Wolves has sparked intense interest.

The US ambassador to Ankara was quizzed for his reaction to the film on a major news channel; even Turkey's foreign minister has felt moved to comment on it. Both were anxious to appear conciliatory.

The film is unashamedly anti-American

But the film clearly capitalises on a wave of anti-American feeling that peaked with the Sulaymaniyah controversy, but began to swell with preparation for the invasion of Iraq.

Middle East expert Cengiz Candar says the incident in Sulaymaniyah added deep insult to injury in Turkey, where there was already strong opposition to the war across the border.

Fears of nationalism

Cengiz Candar feels relations had started to improve. Now he fears Valley of the Wolves will reignite the embers, with all its talk of defending Turkish honour and pride.

"This film poisons the climate in a way that enhances jingoistic nationalism among Turks," Cengiz complains.

"It's pushing society to be inward-looking and hostile to our allies and would-be allies. This kind of mentality will do no good for Turkey."

Part of the pull for the crowds flocking to cinemas here is certainly the Turkish actors involved.

The film is a spin-off from a cult TV series from the same producers.

That show pitted the all-action hero Polat against the Turkish mafia. But in changing the enemy and the location, the team behind the film appear to have judged the public mood well.

Back at the multiplex there was an all-round vote of approval from the audience for the movie, and general disapproval for the US.

"Everything we've been hearing on the news about Iraq is in this film," one woman says as she emerges from the auditorium.

"We condemn this war and will continue to condemn it. But I don't see America as our fundamental enemy," she adds.